1. Field of the Invention
The present invention relates to a vacuum circuit breaker, in particular to a switching mechanism of a vacuum circuit breaker. In more particular, the present invention relates to a switching mechanism of a vacuum circuit breaker which is capable of guaranteeing the credibility of its operation by restraining distortion of each component and installing additional components easily in order to perform multifunction.
2. Description of the Prior Art
Generally, a circuit breaker is for switching an electric circuit in order to protect a load unit or a load line from abnormal current caused by abnormal situations such as a short circuit occurrence on electric circuits from a power plant or a substation to an electric facility of a consumer, the circuit breaker is divided into an AC circuit breaker and a DC circuit breaker according to an applied line, and it is divided into a vacuum circuit breaker and a gas circuit breaker according to an arc shielding medium when the contact is switching.
Generally, inside of the circuit breaker is vacuum or is filled with an insulating material, and an arc-extinguishing unit for shielding arc generated in the switching operation of a fixed contactor and a movable contactor installed in the vacuum area or insulating material filled area is disposed in the circuit breaker. A switching mechanism for providing driving force is connected to an extended end of the movable contactor exposed-installed from the sealed area in order to contact or separate the movable contactor to/from the fixed contactor.
The conventional switching mechanism for the vacuum circuit breaker will now be described with reference to accompanying FIG. 1. The construction and operation of the conventional switching mechanism for the vacuum circuit breaker is referable in the U.S. Pat. No. 5,140,117.
In the conventional switching mechanism for the vacuum circuit breaker, the end portion of a switch lever 111 having a long plate shape is connected to a movable contact portion 105, the switch lever 111 is installed centering around a first rotating shaft 113 so as to be movable to a turn-ON position or turn-OFF position where the movable contactor 105 and fixed contactor 103 are mutually contacted or separated in order to contact or separate the movable contactor 105 to/from the fixed contactor 103. A lever driving unit 121 comprises a cut-off spring 117 coupled to the switch lever 111 in order to drive the switch lever 111. One end portion of an arm 115 is coupled to the other end portion of the switch lever 111, the other end portion of the arm 115 is contacted to the lever driving unit 121. A slave roller 116 is coupled to a free end portion as the other end portion of the arm 115 so as to be rotatable in order to be transferred by contacting a cam. The cut-off spring 117 is combined to the first rotation shaft 113 with a certain distance in order to press the switch lever 111 elastically to the turn-OFF position.
Hereinafter, the structure of the lever driving unit 121 will now be described in detail.
Conventionally, the lever driving unit 121 of the switching mechanism for the circuit breaker comprises a second rotating shaft 124 fixed on a base plate 121a. An end portion of a turn-on spring 135 is combined to the second rotating shaft 124. The cam 129 is coupled to the rotating shaft 131 coupled to the other end portion of the turn-on spring 135 so as to be rotatable, and performs a relative motion by contacting mutually to the slave roller 116. A supporting unit 123 is coupled to the rotating shaft 131 so as to be rotatable in order to rotate centering around the turn-on spring 135. A turn-on latch 137 is coupled to the side of the cam 129 so as to be rotational in order to make the turn-on spring 135 maintain an extension state by restraining the rotation of the cam 129. A trip latch 139 is installed on the free end portion of the supporting unit 123 in order to prevent the supporting unit 123 from rotating by being pressed by the cut-off spring 117. A stopper 127 is installed on the side of the trip latch 139 in order to restrain the rotation of the supporting unit 123 by contacting mutually with the supporting unit 123.
The cam 129 is installed so as to rotate centering around the rotating shaft 131 projected from the plate surface of the supporting unit 123, and the other end portion of the turn-on spring 135 is combined to the side of the cam 129 in order to rotate the cam 129.
And, a stopper pin 133 is protrusively disposed on the side surface of the cam 129, a roller 134 is installed on the stopper pin 133 so as to be rotational in order to contact the free end portion of the turn-on latch 137.
Hereinafter, the operation of the conventional switching mechanism for the vacuum circuit breaker will now be described.
First, in order to make the movable contactor contact to the fixed contactor 103, the turn-on 137 rotates in order to separate from the roller 134 of the stopper pin 133 of the cam 129.
By the above said operation, the turn-on latch 137 is separated from the roller 134, as depicted in FIG. 2, at the same time the cam 129 rotates to the clockwise direction by the tensile force of the turn-on spring 135.
According to the rotation of the cam 129, the slave roller 116 is pressed so as to separate from the rotating shaft 131 of the cam 129, accordingly the switch lever 111 rotates toward the turn-ON position centering around the first rotating shaft 113.
According to the rotation of the switch lever 111, the fixed contactor 103 and movable contactor 105 are contacted each other, the cut-off spring 117 is elastically energized by being extended according with the rotation of the switch lever 111.
On the contrary, in order to make the movable contactor 105 separate from the fixed contactor 103, the trip latch 139 rotates in order to separate from the end portion of the supporting unit 123.
According to the rotation, when the trip latch 139 is separated from the supporting unit 123, as depicted in FIG.2, the switch lever 111 rotates to the counter clock-wise direction centering around the first rotating shaft 113 by the tensile force of the cut-off spring 117. According to this, the supporting member 123 rotates temporarily centering around the second rotating shaft 124, but the rotation of the supporting unit 123 is stopped by contacting to the stopper 127.
Accordingly, according to the rotation of the switch lever 111, the movable contactor 105 is separated from the fixed contactor 103.
However, in the conventional vacuum circuit breaker, the supporting unit rotates centering around the second rotating shaft by the tensile force of the cut-off spring, and the rotation is stopped by contacting with the stopper 127 with an impact on the both supporting unit 123 and stopper 127. When the operation is performed repeatedly, the distortion and separation of the construction parts including the cam can occur due to the impact force caused by the contact between the supporting unit 123 and stopper 127. And, it may causes below problems.
First, the credibility of the apparatus can be lower because the turn-on or
Turn-off operation may not be performed smoothly due to the distortion of the construction parts caused by the impact force.
Second, in the conventional vacuum circuit breaker, the eccentric-installed switch lever and arm supported by the cut-off spring and the cam supported by the turn-on spring are suspended on the lower portion of the each spring, and the fixed supporting position for each spring is same as upper position.
Moreover, the switch lever is made with a steel plate having long length and the cam is made with the steel plate having long width, the gravity of the switch lever and cam have a bad effect on the compression/extension operation of the springs for contacting or separating the movable contactor to or from the fixed contactor. In particular, because the conventional vacuum circuit breaker uses a two link having the switch lever and operating arm, the gravity of the two link is more concentrated on the cut-off spring than the gravity of a multi link.
Third, when there is a need to add a new function, additional installation is difficult because the lever operating unit comprising the two springs and cam is constructed as the one assembly unit.
Fourth, the life span of the circuit breaker can lower due to over-energizing of the turn-on spring because there is no detecting means for detecting the energizing completion of the turn-on spring when the turn-on spring is elastically energized.
Fifth, in the conventional vacuum circuit breaker, there is no displaying means for displaying the energizing completion state or energizing energy exhaustion state of the turn-on spring, accordingly it is inconvenient for a user to use the circuit breaker.
Sixth, there is no displaying means for displaying the turn-ON or turn-OFF state of the main circuit, accordingly it is inconvenient for the user to use the circuit breaker.
The object of the present invention is to provide a switch device for a vacuum circuit breaker which is capable of solving the above-mentioned problems.
The first problem of the conventional technology can be solved by providing the switch device for the vacuum circuit breaker according to the present invention which does not comprises a stopper restricting the rotation of a supporting unit.
The second problem of the conventional technology can be solved by  less than providing the switching mechanism for the vacuum circuit breaker which comprises a first and a second spring for providing power for contacting movable contactor the fixed contactor or separating the movable contactor from the fixed contactor, wherein the first spring being providable the power for contacting the movable contactor to the fixed contactor when it is elastically energized, and the second spring being providable the power for separating the movable contactor from the fixed contactor when it is elastically energized, each of the first and second spring having one end portion being a operating point for providing the power and the other end portion for providing a supporting point to be extended or compressed, each of said other end portions of the first and second spring being placed to be vertically opposite;
a plurality of link means for providing the power provided from the first spring or the second spring to the movable contactor; and a spring energizing means for energizing at least one spring among the first and second spring.
The third problem of the conventional technology can be solved by providing the vacuum circuit breaker according to the present invention which is capable of installing easily a new function mean such as a displaying mean for displaying an original position return state or extension state of the turn-on spring or displaying a turn-ON (ON) state or turn-OFF (OFF) state of the circuit breaker.
The fourth problem of the conventional technology can be solved by providing the vacuum circuit breaker according to the present invention which comprises a driving wheel including a gear portion for receiving the power on the outer circumference and a gearless portion for detecting the energizing completion of the turn-on spring on the outer circumference.
The fifth problem of the conventional technology can be solved by providing the vacuum circuit breaker comprising a display plate including a display unit which is co-axially connected to the rotating shaft of the driving arm in order to rotate according to the rotation of the driving arm and display the energizing state or energizing energy exhaustion state of the spring on the front plate of the vacuum circuit breaker, and a see through window installed on the front surface of the vacuum circuit breaker in order to watch the display unit of the display plate.
The sixth problem of the present invention can be solved by providing the vacuum circuit breaker comprising a display plate including a display unit which is co-axially connected to the rotating shaft of the switch lever in order to rotate according to the rotation of the switch lever and display the turn-ON or turn-OFF state of the main circuit on the upper surface, and a see through window installed on the front surface of the vacuum circuit breaker in order to watch the display unit of the display plate.